U.S. patent number 9,580,960 [Application Number 15/089,137] was granted by the patent office on 2017-02-28 for aerial ladder for a fire apparatus.
This patent grant is currently assigned to Oshkosh Corporation. The grantee listed for this patent is Oshkosh Corporation. Invention is credited to Jeffrey D. Aiken, Eric D. Betz, Jennifer L. Bloemer.
United States Patent |
9,580,960 |
Aiken , et al. |
February 28, 2017 |
Aerial ladder for a fire apparatus
Abstract
An aerial ladder assembly for a fire apparatus includes a first
truss member, a second truss member, and a plurality of rungs
coupling the first truss member to the second truss member. The
first truss member includes a first base rail, a first hand rail
elevated from the first base rail, and a plurality of lacing
members coupling the first base rail to the first hand rail. The
second truss member includes a second base rail, a second hand rail
elevated from the second base rail, and a plurality of lacing
members coupling the second base rail to the second hand rail. The
first truss member and the second truss member define a first zone
and a second zone separated by a transition, and the first base
rail and the second base rail have a first shape within the first
zone and a second shape within the second zone.
Inventors: |
Aiken; Jeffrey D. (Neenah,
WI), Betz; Eric D. (Clintonville, WI), Bloemer; Jennifer
L. (DePere, WI) |
Applicant: |
Name |
City |
State |
Country |
Type |
Oshkosh Corporation |
Oshkosh |
WI |
US |
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Assignee: |
Oshkosh Corporation (Oshkosh,
WI)
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Family
ID: |
54697668 |
Appl.
No.: |
15/089,137 |
Filed: |
April 1, 2016 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20160215560 A1 |
Jul 28, 2016 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14552240 |
Nov 24, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60R
3/02 (20130101); E06C 5/02 (20130101); E06C
5/04 (20130101); A62C 27/00 (20130101) |
Current International
Class: |
E06C
5/04 (20060101); B60R 3/02 (20060101); E06C
5/02 (20060101); A62C 27/00 (20060101) |
Field of
Search: |
;182/69.4,106,207,198
;280/4 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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203050481 |
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Jul 2013 |
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CN |
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36 40 944 |
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Jun 1988 |
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DE |
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0 244 668 |
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Nov 1987 |
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EP |
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H11-239625 |
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Sep 1999 |
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JP |
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2008-297701 |
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Dec 2008 |
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JP |
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20110040306 |
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Apr 2011 |
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KR |
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101297477 |
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Aug 2013 |
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KR |
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Other References
US. Appl. No. 08/046,623, filed Apr. 14, 1993, Schmitz et al. cited
by applicant .
U.S. Appl. No. 09/123,8904, filed Jul. 28, 1998, Archer et al.
cited by applicant .
U.S. Appl. No. 09/364,690, filed Jul. 30, 1999, Kempen et al. cited
by applicant .
U.S. Appl. No. 10/171,075, filed Jun. 13, 2002, Archer et al. cited
by applicant .
U.S. Appl. No. 29/162,282, filed Jun. 13, 2002, Archer et al. cited
by applicant .
U.S. Appl. No. 29/1692,344, filed Jun. 13, 2002, Archer et al.
cited by applicant .
Anonymous, "New truck for Lincolnshire-Riverwoods," Chicago Area
Fire Departments, Dec. 6, 2010, Retrieved from the Internet at
http://chicagoareafire.com/blog/2010/12/06/ on Jan. 26, 2016, 5
pages as printed. cited by applicant .
Firehouse, "Problems with single axle aerial trucks," Firehouse,
Dec. 2, 2009, Retrieved from the Internet at
http://www.firehouse.com/forums/t111822/ on Jan. 25, 2016, 15 pages
as printed. cited by applicant .
Rosenbauer, "Raptor Aerials" Oct. 2, 2014, Retrieved from the
Internet at
https://web.archive.org/web/20141002023939/http://rosenbaueramerica.com/m-
edia/documents/pdf/raptor.sub.--eng.pdf on Jan. 25, 2016, 6 pages
as printed. cited by applicant .
Rosenbauer, "Viper Aerials," Rosenbauer, Oct. 2, 2014, Retrieved
from the Internet at
https://web.archive.org/web/20141002023939/http://rosenbaueramerica.com/m-
edia/documents/pdf/viper.sub.--eng.pdf on Jan. 25, 2016, 8 pages as
printed. cited by applicant .
International Search Report and Written Opinion for PCT Application
No. PCT/US2015/059984, mail date Feb. 10, 2016, 11 pages. cited by
applicant .
International Search Report and Written Opinion for PCT Application
No. PCT/US2015/060034, mail date Feb. 4, 2016, 12 pages. cited by
applicant .
International Search Report and Written Opinion for PCT Application
No. PCT/US2015/060035, mail date Feb. 10, 2016, 16 pages. cited by
applicant .
International Search Report and Written Opinion for PCT Application
No. PCT/US2015/060036, mail date Feb. 9, 2016, 14 pages. cited by
applicant .
International Search Report and Written Opinion for PCT Application
No. PCT/US2015/060038, mail date Feb. 22, 2016, 16 pages. cited by
applicant .
International Search Report and Written Opinion for PCT Application
No. PCT/US2015/060040, mail date Feb. 9, 2016, 15 pages. cited by
applicant .
Non-Final Office Action on U.S. Appl. No. 14/552,283, mail date May
9, 2016, 8 pages. cited by applicant .
Non-Final Office Action on U.S. Appl. No. 14/552,293 mail date May
10, 2016, 13 pages. cited by applicant .
Notice of Allowance on U.S. Appl. No. 14/552,275 Dated Nov. 8,
2016, 10 pages. cited by applicant.
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Primary Examiner: Knutson; Jacob
Attorney, Agent or Firm: Foley & Lardner LLP
Parent Case Text
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
This application is a continuation of U.S. application Ser. No.
14/552,240, titled "Aerial Ladder for a Fire Apparatus, filed Nov.
24, 2014 and is related to U.S. application Ser. No. 14/552,252,
titled "Quint Configuration Fire Apparatus," filed Nov. 24, 2014;
U.S. application Ser. No. 14/552,260, titled "Turntable Assembly
for a Fire Apparatus," filed Nov. 24, 2014; U.S. application Ser.
No. 14/552,275, titled "Ladder Assembly for a Fire Apparatus,"
filed Nov. 24, 2014; U.S. application Ser. No. 14/552,283, titled
"Pedestal and Torque Box Assembly for a Fire Apparatus," filed Nov.
24, 2014; and U.S. application Ser. No. 14/552,293, titled
"Outrigger Assembly for a Fire Apparatus," filed Nov. 24, 2014, all
of which are incorporated herein by reference in their entireties.
Claims
What is claimed is:
1. An aerial ladder assembly for a fire apparatus, comprising: a
first truss member including a first base rail, a first hand rail
elevated from the first base rail, and a plurality of lacing
members coupling the first base rail to the first hand rail,
wherein the first truss member extends along a longitudinal
direction; a second truss member including a second base rail, a
second hand rail elevated from the second base rail, and a
plurality of lacing members coupling the second base rail to the
second hand rail, wherein the second truss member extends along the
longitudinal direction; and a plurality of rungs coupling the first
truss member to the second truss member, the plurality of rungs
extending across the longitudinal direction, wherein the first
truss member and the second truss member define a first zone and a
second zone separated by a transition, the first base rail and the
second base rail each comprising a first tubular member and a
second tubular member within the first zone that are fixed together
to provide at least portions of the first base rail and the second
base rail, wherein the second tubular members are disposed inward
of the first tubular members, wherein the first base rail and the
second base rail each have a first shape within the first zone and
a second shape within the second zone, and wherein the first shape
is different than the second shape.
2. The aerial ladder assembly of claim 1, wherein the second
tubular members of the first base rail and the second base rail
terminate at the transition, the first tubular members continuing
through the second zone of the first truss member and the second
truss member.
3. The aerial ladder assembly of claim 2, further comprising a
brace coupling the first tubular members and the second tubular
members of the first base rail and the second base rail.
4. The aerial ladder assembly of claim 3, wherein the brace
includes a top plate and a side leg, wherein the side leg is
angularly offset relative to the top plate.
Description
BACKGROUND
Aerial ladders may be provided on a mobile platform or a vehicle,
such as a fire apparatus (e.g., a fire truck, etc.). Such aerial
ladders are extendable structures having components that telescope
relative to one another. Fire fighters may pivot and extend the
aerial ladder upward and outward from the fire apparatus to
advantageously elevate and position an end of the aerial ladder. By
way of example, the end of the aerial ladder may include a nozzle,
and positioning the nozzle may facilitate discharge of water
therefrom. By way of another example, the end of the aerial ladder
may include a platform or basket, and positioning the end of the
aerial ladder may facilitate a rescue operation.
The aerial ladder is coupled to the fire apparatus at one end. When
pivoted upward, the aerial ladder forms a cantilever structure that
is subject to loading from the weight of the aerial ladder itself
and to loading from any persons or equipment on the aerial ladder.
Such loading causes deflection along the length of the aerial
ladder. Aerial ladders are designed using materials and structural
components that reduce deflection at the end of the aerial
ladder.
SUMMARY
One embodiment relates to an aerial ladder assembly for a fire
apparatus that includes a first truss member, a second truss
member, and a plurality of rungs coupling the first truss member to
the second truss member. The first truss member includes a first
base rail, a first hand rail elevated from the first base rail, and
a plurality of lacing members coupling the first base rail to the
first hand rail. The second truss member includes a second base
rail, a second hand rail elevated from the second base rail, and a
plurality of lacing members coupling the second base rail to the
second hand rail. The first truss member and the second truss
member extend along a longitudinal direction, and the plurality of
rungs extend across the longitudinal direction. The first truss
member and the second truss member define a first zone and a second
zone separated by a transition, and the first base rail and the
second base rail have a first shape within the first zone and a
second shape within the second zone.
The invention is capable of other embodiments and of being carried
out in various ways. Alternative exemplary embodiments relate to
other features and combinations of features as may be recited
herein.
BRIEF DESCRIPTION OF THE DRAWINGS
The disclosure will become more fully understood from the following
detailed description, taken in conjunction with the accompanying
figures, wherein like reference numerals refer to like elements, in
which:
FIG. 1 is a front perspective view of a fire apparatus, according
to an exemplary embodiment;
FIG. 2 is a perspective view of a ladder assembly for a fire
apparatus, according to an exemplary embodiment;
FIG. 3 is a detail perspective view of a ladder assembly of FIG.
2;
FIG. 4 is a sectional view of a truss member of the ladder assembly
of FIG. 2;
FIG. 5 is a perspective view of a section of a lower longitudinal
member of the ladder assembly of FIG. 2;
FIG. 6 is a perspective view of a section of a lower longitudinal
member of the ladder assembly of FIG. 2;
FIG. 7 is a detail perspective view of the ladder assembly of FIG.
2;
FIG. 8 is a side plan view of the ladder assembly of FIG. 2;
FIG. 9 is a detail lower perspective view of the ladder assembly of
FIG. 2; and
FIG. 10 is a cross-sectional view of a multi-section ladder
assembly, according to an alternative embodiment.
DETAILED DESCRIPTION
Before turning to the figures, which illustrate the exemplary
embodiments in detail, it should be understood that the present
application is not limited to the details or methodology set forth
in the description or illustrated in the figures. It should also be
understood that the terminology is for the purpose of description
only and should not be regarded as limiting.
According to an exemplary embodiment, an aerial ladder assembly is
operable within a work envelope defined at least in part by a
vertical extension height and a horizontal reach distance. The
aerial ladder assembly has a structural truss design that reduces
weight while improving vertical extension height and horizontal
reach. Traditionally, a "Quint" configuration fire apparatus (e.g.,
a fire apparatus having a fire fighting ladder mounted on a single
rear axle chassis, etc.) has a vertical extension height of 75-80
feet and 67-72 feet of horizontal reach. Traditionally, increasing
extension height or horizontal reach requires increasing the weight
of the aerial ladder assembly and supporting the aerial ladder
assembly with a tandem rear axle chassis. A tandem rear axle may
include two solid axle configurations or may include two pairs of
axles (e.g., two pairs of half shafts, etc.) each having a set of
constant velocity joints and coupling two differentials to two
pairs of hub assemblies. A single rear axle chassis may include one
solid axle configuration or may include one pair of axles each
having a set of constant velocity joints and coupling a
differential to a pair of hub assemblies, according to various
alternative embodiments. According to an exemplary embodiment of
the present Application, the aerial ladder assembly has a vertical
extension height of at least 95 feet (e.g., 105 feet, 107 feet,
etc.) and at least 90 feet (e.g., at least 100 feet, etc.) of
horizontal reach with a tip capacity of at least 750 pounds and may
be supported by a single rear axle chassis.
According to the exemplary embodiment shown in FIG. 1, a vehicle,
shown as a fire apparatus 10, includes a chassis, shown as a frame
12, that defines a longitudinal axis 14. A body assembly, shown as
rear section 16, axles 18, and a cab assembly, shown as front cabin
20, are coupled to frame 12. In one embodiment, the longitudinal
axis 14 is generally aligned with a frame rail of the fire
apparatus 10 (e.g., front to back, etc.).
Referring still to the exemplary embodiment shown in FIG. 1, the
front cabin 20 is positioned forward of the rear section 16 (e.g.,
with respect to a forward direction of travel for the vehicle along
the longitudinal axis 14, etc.). According to an alternative
embodiment, the cab assembly may be positioned behind the rear
section 16 (e.g., with respect to a forward direction of travel for
the vehicle along the longitudinal axis 14, etc.). The cab assembly
may be positioned behind the rear section 16 on, by way of example,
a rear tiller fire apparatus. In some embodiments, the fire
apparatus 10 is a ladder truck with a front portion that includes
the front cabin 20 pivotally coupled to a rear portion that
includes the rear section 16.
As shown in FIG. 1, the fire apparatus 10 is an aerial truck that
includes an aerial ladder assembly, shown as aerial ladder assembly
30. While shown attached to fire apparatus 10, aerial ladder
assembly 30 may be coupled to various types of vehicles (e.g.,
rescue vehicles, defense vehicles, lift vehicles, etc.). Aerial
ladder assembly 30 includes a first end 32 (e.g., base end,
proximal end, pivot end, etc.) and a second end 33 (e.g., free end,
distal end, platform end, implement end, etc.). While shown as a
single ladder section, aerial ladder assembly 30 may include a
plurality of extensible ladder sections and have a first end 32 and
a second end 33. According to an exemplary embodiment, aerial
ladder assembly 30 is coupled to frame 12 at first end 32. By way
of example, aerial ladder assembly 30 may be directly coupled to
frame 12 or indirectly coupled to frame 12 (e.g., with an
intermediate superstructure, etc.). As shown in FIG. 1, the first
end 32 of aerial ladder assembly 30 is coupled to a turntable 34.
Turntable 34 may be directly or indirectly coupled to frame 12
(e.g., with an intermediate superstructure, via rear section 16,
etc.). According to an exemplary embodiment, turntable 34 rotates
relative to the frame 12 about a generally vertical axis 35.
According to an exemplary embodiment, the turntable 34 is rotatable
a full 360 degrees relative to the frame 12. In other embodiments,
the rotation of the turntable 34 relative to the frame 12 is
limited to a range less than 360 degrees or the turntable 34 is
fixed relative to the frame 12. According to the exemplary
embodiment shown in FIG. 1, the turntable 34 is positioned at the
rear end of the rear section 16 (e.g., rear mount, etc.). In other
embodiments, the turntable 34 is positioned at the front end of the
rear section 16, proximate the front cabin 20 (e.g., mid mount,
etc.). In still other embodiments, the turntable 34 is disposed
along front cabin 20 (e.g., front mount, etc.).
According to the exemplary embodiment shown in FIG. 1, first end 32
is pivotally coupled to the turntable 34 such that the aerial
ladder assembly 30 may be rotated about a generally horizontal axis
37 with an actuator, shown as hydraulic cylinder 36. The actuator
may be a linear actuator, a rotary actuator, or still another type
of device and may be powered hydraulically, electrically, or still
otherwise powered. In one embodiment, aerial ladder assembly 30 is
rotatable between a generally horizontal lowered position (e.g.,
the position shown in FIG. 1, etc.) and a raised position. In one
embodiment, extension and retraction of hydraulic cylinders 36
rotates aerial ladder assembly 30 about the horizontal axis 37 and
raises or lowers, respectively, the second end 33 of aerial ladder
assembly 30. In the raised position, the aerial ladder assembly 30
allows access between the ground and an elevated height for a fire
fighter or a person being aided by the fire fighter.
Referring still to the exemplary embodiment shown in FIG. 1, an
implement, shown as nozzle 38 (e.g., deluge gun, water cannon, deck
gun, etc.) is disposed at the second end 33 of the aerial ladder
assembly 30. The nozzle 38 is connected to a water source at ground
level via intermediate conduit extending along the aerial ladder
assembly 30 (e.g., along the side of the aerial ladder assembly 30,
beneath the aerial ladder assembly 30, in a channel provided in the
aerial ladder assembly 30, etc.). By pivoting the aerial ladder
assembly 30 to the raised position, the nozzle 38 may be elevated
to expel water from a higher elevation and facilitate suppressing a
fire. In some embodiments, the second end 33 of the aerial ladder
assembly 30 includes a basket. The basket may be configured to hold
at least one of fire fighters and persons being aided by the fire
fighters. The basket provides a platform from which a fire fighter
may complete various tasks (e.g., operate the nozzle 38, create
ventilation, overhaul a burned area, perform a rescue operation,
etc.).
In some embodiments, aerial ladder assembly 30 is extendable and
includes a plurality of sections that may be actuated between an
extended configuration and a retracted configuration. By way of
example, aerial ladder assembly 30 may include multiple, nesting
sections that telescope with respect to one another. In the
extended configuration (e.g., deployed position, use position,
etc.), the aerial ladder assembly 30 is lengthened, and the second
end 33 is extended away from the first end 32. In the retracted
configuration (e.g., storage position, transport position, etc.),
the aerial ladder assembly 30 is shortened to withdraw the second
end 33 towards the first end 32.
The aerial ladder assembly 30 forms a cantilever structure.
According to the exemplary embodiment shown in FIG. 1, aerial
ladder assembly 30 is supported by the hydraulic cylinders 36 and
by the turntable 34 at the first end 32. The aerial ladder assembly
30 supports static loading from its own weight, the weight of any
equipment coupled to the ladder (e.g., the nozzle 38, a water line
coupled to the nozzle, a platform, etc.), and the weight of any
persons using the ladder. Aerial ladder assembly 30 may also be
subjected to various dynamic loads (e.g., due to forces imparted by
a fire fighter climbing aerial ladder assembly 30, wind loading,
loading due to rotation, elevation, or extension of aerial ladder
assembly, etc.). Such static and dynamic loads are carried by
aerial ladder assembly 30. The forces carried by the hydraulic
cylinders 36, the turntable 34, and frame 12 may be proportional
(e.g., directly proportional, etc.) to the length of the aerial
ladder assembly 30. Increasing at least one of the extension height
rating, the horizontal reach rating, the static load rating, and
the dynamic load rating traditionally increases the weight of
aerial ladder assembly 30, the weight of turntable 34, or the
weight of hydraulic cylinders 36, among other components, and
traditionally requires the use of a chassis having two rear axles.
Aerial ladder assembly 30 has an increased extension height rating
and horizontal reach rating without requiring a chassis having two
rear axles (e.g., a tandem axle assembly, etc.), according to an
exemplary embodiment. Aerial ladder assembly 30 described herein
has an improved strength to weight ratio, thereby allowing for an
aerial ladder assembly 30 having an increased extension height an
horizontal reach to be utilized on the fire apparatus 10 having a
single rear axle 18. Fire apparatus 10 having a single rear axle 18
is smaller, lighter, more maneuverable, and less expensive to
manufacture than fire apparatuses having two rear axles. According
to an exemplary embodiment, the aerial ladder assembly 30 for the
fire apparatus 10 has an extension height rating of at least 95
feet (e.g., 105 feet, 107 feet, etc.) and a horizontal reach rating
of at least 90 feet (e.g., at least 100 feet, etc.).
Referring next to FIGS. 2-4, the aerial ladder assembly 30 includes
a plurality of structural members. In some embodiments, the aerial
ladder assembly 30 is a section (e.g., a fly section, etc.) of a
telescoping ladder. According to the exemplary embodiment shown in
FIGS. 2-4, aerial ladder assembly 30 includes a pair of truss
members, shown as truss members 40. Truss members 40 are structural
members, according to an exemplary embodiment, that carry static
and dynamic loading experienced by aerial ladder assembly 30. In
one embodiment, truss members 40 are generally parallel and extend
along a longitudinal direction. As shown in FIGS. 2-4, a plurality
of cross members, shown as rungs 42, couple the first truss member
40 to the second truss member 40. In one embodiment, rungs 42
extend laterally between truss members 40 (e.g., across the
longitudinal direction along which truss members 40 extend, etc.).
As shown in FIGS. 2-4, rungs 42 are supported by braces, shown as
rung supports 44.
According to an exemplary embodiment, the truss members 40 each
include a lower longitudinal member, shown as base rail 46 (e.g.,
lower rail, bottom rail, etc.), and an upper longitudinal member,
shown as hand rail 48 (e.g., upper rail, top rail, etc.). As shown
in FIGS. 2-4, base rails 46 are separated an offset distance from
one another, and hand rails 48 are elevated relative to base rails
46. The base rails 46 are coupled to the hand rails 48 by a
plurality of supports, shown as lacing members 50 and lacing
members 52. As shown in FIGS. 2-4, lacing members 50 are angled
relative to base rails 46 and hand rails 48. Lacing members 52 are
perpendicular to base rails 46 and hand rails 48, according to an
exemplary embodiment. In one exemplary embodiment, truss members 40
are generally vertically oriented, with each base rail 46 and
corresponding hand rail 48 extending within the same vertical
planes. According to an alternative embodiment, truss members 40
are inclined relative to one another (e.g., disposed at an offset
angle relative to one another, etc.), such that the distance
between the base rails 46 of the truss members 40 is different than
the distance between the hand rails 48 of the truss members 40.
As shown in the sectional view of FIG. 4, truss member 40 includes
a plurality of tubular components. According to an exemplary
embodiment, hand rail 48 is a hollow, tubular member. Hand rail 48
may be a single, continuous tubular element or may include a
plurality of tubular elements that are coupled (e.g., welded, etc.)
end-to-end. As shown in FIG. 4, hand rail 48 includes a tubular
member having a rectangular cross sectional shape. In other
embodiments, hand rail 48 has a different cross sectional shape
(e.g., round, oval, hexagonal, etc.). In still other embodiments,
hand rail 48 includes a different arrangement of structural
components (e.g., a pair of tubular members, a solid angle element,
a solid channel, a bar, etc.).
Referring still to FIG. 4, base rail 46 includes a first member 54
and a second member 56. According to the exemplary embodiment shown
in FIG. 4, first member 54 is disposed inward of second member 56
(e.g., first member 54 is disposed closer to a centerline of aerial
ladder assembly 30, etc.). As shown in FIG. 4, first member 54 and
second member 56 are hollow rectangular tubes. In one embodiment,
first member 54 and second member 56 each have two side walls 64
extending between a top wall 60 and a bottom wall 62. According to
an exemplary embodiment, the first member 54 and is positioned
along the second member 56 such that a side wall 64 of the first
member 54 abuts a side wall 64 of the second member 56. In some
embodiments, the side walls 64 of the first member 54 and the
second member 56 are welded together along an interface of the side
walls 64. By way of example, the first member 54 and the second
member 56 may be welded together along a joint at the top or bottom
of the side walls 64. In other embodiments, the first member 54 and
the second member 56 are welded together along top walls 60 or
bottom walls 62 (e.g., with spot welds, etc.). Using thin-walled
rectangular tubular components reduces the cost of aerial ladder
assembly 30.
Referring again to FIG. 2, the aerial ladder assembly 30 has a
first zone 80 and a second zone 82 separated by a transition point
84. According to an exemplary embodiment, base rails 46 have a
shape (e.g., cross sectional shape, cross sectional area, thickness
of material for the structural components, number of structural
components, etc.) that corresponds to a particular length or length
range along aerial ladder assembly 30. The shape of base rails 46
may vary along the length of aerial ladder assembly 30. By way of
example, the base rails 46 may have a first shape within first zone
80 and a second shape within second zone 82. Such base rails 46 may
be tuned to the particular loading experienced by the particular
length or length range of aerial ladder assembly 30. According to
an exemplary embodiment, the first zone 80 is proximate to the
first end 32 of the aerial ladder assembly 30 and the second zone
82 is proximate the second end 33 of the aerial ladder assembly 30.
In one embodiment, the base rails 46 along first zone 80 include
both the first member 54 and second member 56 while the base rails
46 along the second zone 82 include only one rail (e.g., the first
member 54, etc.). By way of example, the first member 54 may
continue along both the first zone 80 and the second zone 82 of
each the truss member 40. One of the rails (e.g., the second member
56, etc.) may terminate at the transition point 84 between the
first zone 80 and the second zone 82. As shown in FIG. 2, the
second member 56 tapers to an end 86 at the transition point
84.
In one embodiment, the aerial ladder assembly 30 is unsupported at
the second end 33. The bending moments generated by the various
loads imparted on the aerial ladder assembly 30 are smaller at
second end 33 and larger at first end 32, where the aerial ladder
assembly 30 is coupled to the turntable 34 and to the hydraulic
cylinders 36. According to an exemplary embodiment, base rails 46
include two tubular elements (e.g., first member 54 and second
member 56, etc.) to carry the increased bending moment experienced
by first zone 80 of aerial ladder assembly 30. Aerial ladder
assembly 30 having base rails 46 that include a single tubular
element (e.g., only first member 54, etc.) along second zone 82 has
an increased strength-to-weight ratio.
Referring next to FIGS. 5-6, base rails 46 include various
components that are coupled (e.g., welded, etc.) together.
According to an exemplary embodiment, at least one of the first
member 54 and the second member 56 include a plurality of
components that are positioned end-to-end. By way of example, first
member 54 may include a first section 54a and a second section 54b
while second member 56 may include a first section 56a and a second
section 56b. The various portions of first member 54 and second
member 56 may have lengths that are shorter than the overall length
of base rails 46. As shown in FIGS. 5-6, a brace, shown as brace
68, is disposed at a union 66 of the first and second portions of
first member 54 and second member 56. The brace 68 is positioned
along the top walls 60 of first member 54 and second member 56 and
spans union 66, according to an exemplary embodiment. As shown in
FIGS. 5-6, brace 68 has an "L"-shaped cross-section and includes a
top plate 70 and a side leg 72. In one embodiment, side leg 72 is
angularly offset (e.g., ninety degrees, etc.) relative to top plate
70. Side leg 72 may facilitate positioning brace 68 atop first
member 54 and second member 56, thereby simplifying manufacturing.
In one embodiment, brace 68 is manufactured by bending a sheet of
material to form top plate 70 and side leg 72. As shown in FIGS.
5-6, the brace 68 is positioned such that the top plate 70 abuts
the top walls 60 of the first member 54 and the second member 56
and the side leg 72 abuts the outer side wall 64 of the first
member 54. According to an exemplary embodiment, the brace 68 has a
width that is approximately equal to the combined widths of the
first member 54 and the second member 56 such that a distal edge 74
of the top plate 70 does not extend beyond the outer side wall 64
of the first member 54 when the brace 68 is positioned on the first
member 54 and the second member 56. The side leg 72 has a height
that is less than the height of the first member 54 to minimize the
weight of the brace 68 and the overall weight of the aerial ladder
assembly 30. In other embodiments, the side leg 72 may have a
height that is approximately equal to the height of the first
member 54. In another embodiment, the brace 68 may be positioned
with the side leg 72 oriented along the inner side wall 64 of the
second member 56. In other embodiments, the brace 68 may have a
second side leg opposite the side leg 72 that is configured to
extend along the inner side wall 64 of the second member 56.
According to an exemplary embodiment, brace 68 facilitates
manufacturing aerial ladder assembly 30. By way of example, the
brace 68 may be used in the manufacturing process as a fixture to
position the first member 54 and second member 56 relative to one
other. In an exemplary embodiment, the first section 54a and the
second section 54b of first member 54 are positioned against the
top plate 70 and the side leg 72 of the brace 68. The first section
54a and the second section 54b of first member 54 may then be
coupled (e.g., welded, etc.) together and/or coupled to the brace
68. The first section 56a and the second section 56b of second
member 56 may then be positioned against the side walls 64 of the
first section 54a and the second section 54b of first member 54 and
against the top plate 70 of the brace 68. The first section 56a and
the second section 56b of second member 56 may then be at least one
of coupled together, coupled to the brace 68, and coupled to the
first member 54.
The brace 68 may be coupled to the first section 54a and the second
section 54b of first member 54 with a weld along a distal edge 76
of the side leg 72. The weld may be continuous and extend along the
length of the brace 68 or may include a plurality of intermittent
welds (e.g., skip welds, etc.). According to an exemplary
embodiment, the brace 68 is coupled to the first section 56a and
the second section 56b of second member 56 along the distal edge 74
of the top plate 70. The weld may be continuous and extend along
the length of the brace 68 or may include a plurality of
intermittent welds (e.g., skip welds, etc.).
Referring next to FIGS. 7-8, the lacing members 50 and the lacing
members 52 couple the hand rails 48 to the base rails 46. According
to an exemplary embodiment, lacing members 50 include lacing
members 50a and lacing members 50b. As shown in FIGS. 7-8, lacing
members 50 extend between hand rails 48 and base rails 46. In one
embodiment, lacing members 50 include ends 51 that abut base rails
46. Ends 51 of lacing members 50 are coupled to base rails 46,
according to an exemplary embodiment. The lacing members 50a and
50b alternate along the length of the aerial ladder assembly 30,
with the ends 51 of the lacing members 50a and 50b meeting at a
plurality of common interfaces, shown as joints 88. As shown in
FIGS. 7-8, joints 88 are disposed along base rails 46 at regular
intervals. In other embodiments, the spacing between joints 88 may
be non-uniform along the length of aerial ladder assembly 30. In
some embodiments, lacing members 52 are provided at one or more of
the joints 88.
According to an exemplary embodiment, aerial ladder assembly 30
includes lacing members 50 and the lacing members 52 that are
manufactured from thin-walled tubular members. Such an aerial
ladder assembly 30 may have a reduced overall weight. In one
embodiment, the arrangement of the various components of aerial
ladder assembly 30 facilitate such construction without sacrificing
load, vertical extension, or horizontal reach ratings. The lacing
members 50 and the lacing members 52 may have a similar
cross-sectional shape or may have different cross-sectional shapes.
According to an exemplary embodiment, lacing members 50 are
circular tubes and lacing members 52 are circular tubes. In other
embodiments, the lacing members 50 and lacing members 52 may be
otherwise shaped. By way of example, the lacing members 50 and the
lacing members 52 may be tubes with a rectangular or hexagonal
cross-sectional shape. In still other embodiments, the lacing
members may be other structural members (e.g., angles, channels,
rods, etc.). The size and/or shape of the lacing members 50 and the
lacing members 52 may vary along the length of the aerial ladder
assembly 30.
Referring still to the exemplary embodiment shown in FIGS. 5-6 and
7-8, the joints 88 between the lacing members 50 and the base rails
46 include reinforcing members, shown as gussets 90. According to
an exemplary embodiment, gusset 90 is a flat plate. As shown in
FIG. 8, gusset 90 is generally trapezoidal and includes an upper
edge 92, a lower edge 94, and two sides 96. According to an
exemplary embodiment, the lower edge 94 of gusset 90 is positioned
along (e.g., abuts, contacts, engages, interfaces with, etc.) the
base rail 46. In one embodiment, the lower edge 94 of gusset 90 is
disposed along a brace 68 positioned at a joint 88. In another
embodiment, the lower edge 94 of gusset 90 is disposed along the
top wall 60 of the first member 54 and/or the second member 56.
According to an exemplary embodiment, gusset 90 is a continuous
body extending from base rail 46 upward into engagement with lacing
members 50. As shown in FIG. 7, lacing members 50 define a
plurality of apertures (e.g., slots, grooves, slits, etc.), shown
as slots 98 that receive gusset 90. Gusset 90 may extend entirely
through lacing member 50 and into direct engagement with base rail
46. In one exemplary embodiment, the plurality of slots 98 are
formed in the lacing members 50 by laser cutting. In other
embodiments, the plurality of slots 98 are otherwise formed (e.g.,
water jet cut, machined, etc.) in the lacing members 50. Intact
portions of lacing members 50 pass around the gusset 90 and
terminate at ends 51. In one embodiment, ends 51 are positioned
along (e.g., abut, contact, engage, interface with, etc.) the base
rail 46. In one embodiment, the ends 51 are disposed along a brace
68 positioned at a joint 88. In another embodiment, the ends 51 are
disposed along the top wall 60 of the first member 54 and/or the
second member 56. As shown in FIGS. 7-8, the ends 51 of the lacing
members 50 may be separated by a gap 89. According to an exemplary
embodiment, ends 51 of lacing members 50 and lower edge 94 of
gusset 90 contact base rail 46, thereby directly transferring
loading and stresses between base rail 46 and lacing members 50. In
one embodiment, an aerial ladder assembly 30 having a gusset 90
that extends through lacing members 50 defines additional load
paths not present in traditional ladder assemblies.
As shown in FIG. 8, the upper edge 92 spans the space between the
lacing members 50. The sides 96 span the space between the lacing
members 50 and the base rail 46. According to an exemplary
embodiment, the upper edge 92 and the sides 96 may be inwardly
curved (e.g., scalloped, etc.). The upper edge 92 and the sides 96
may approach the surface of the lacing members 50 at a relatively
shallow angle, such that the corners 100 of the exposed portions
102 of the gusset 90 approach an angle of 180 degrees. In one
embodiment, gusset 90 having an inwardly curved upper edge 92 and
sides 96 improves load transfer between base rail 46 and lacing
members 50.
The gusset 90 is coupled to the lacing members 50 with welds 104
and welds 106. In one embodiment, welds 104 and welds 106 continue
along a first side of the gusset 90, around a corner 100 of gusset
90, and along an opposing second side of the gusset 90. In some
embodiments, welds 104 and 106 may not extend around the corners
100 but may instead comprise separate welds formed on either side
of the gusset 90. In one embodiment, the gusset 90 defines a single
unitary body that extends from upper edge 92, through outer surface
of the lacing members 50 (e.g., into the slot 98, etc.), and to a
concealed portion 103 within the lacing member 50. Gusset 90
further extends downward from concealed portion 103 to base rail
46. In one embodiment, the single unitary body defines a continuous
load path between the various components of aerial ladder assembly
30. Gusset 90 also reduces stress concentrations within the joint
88. The continuous extension of gusset 90 from upper edge 92 to
concealed portion 103 also improves the likelihood that corners 100
will remain intact during a welding operation (e.g., to reduce the
amount of corner 100 that is melted and assumed into the weld bead,
etc.). A relatively smooth transition is therefore maintained
between the upper edge 92 and the lacing members 50 and between the
sides 96 and the lacing members 50, reducing the stress
concentrations that may otherwise be formed between the lacing
members 50 and the gusset 90. Such a reduction in stress
concentrations facilitates a reduction in the weight of various
components (e.g., lacing members 50, base rails 46, etc.), thereby
reducing the weight of aerial ladder assembly 30.
The lacing members 50 and the gusset 90 are coupled to the base
rail 46 with a weld 108. Weld 108 extends around the base of the
joint 88, coupling the ends 51 of the lacing members 50 and the
lower edge 94 of gusset 90 to the base rail 46. The weld 108 may
couple the ends 51 of the lacing members 50 and the lower edge 94
to a brace 68 or directly to the top wall 60 of the first member 54
and/or the second member 56.
Because the gusset 90 passes through the lacing members 50 via the
slots 98, stresses (e.g., sheer stresses, bending stresses, etc.)
at the joint 88 can flow through the gusset 90 and directly into
the base rail 46 instead of passing through the ends 51 of the
lacing members 50. Aerial ladder assembly 30 may thereby include
smaller lacing members 50 (e.g., smaller in diameter, smaller in
wall thickness, etc.) than truss members having gussets 90 that do
not pass through lacing members 50 or extend downward to base rail
46.
The configuration of the lacing members 50 and the gussets 90 also
aids in the manufacturing of truss members 40 and the structural
integrity of the joints 88. The slots 98 position the gusset 90
relative to the lacing members 50 along a preferred vertical plane
(e.g., a vertical plane passing through the neutral axis of the
lacing members 50, etc.). The slots 98 allow the gusset 90 to be
accurately positioned relative to lacing members 50 without the use
of an additional fixture. The slots 98 thereby reduce the risk that
the gussets 90 will be welded in a skewed orientation (e.g., angled
in a lateral direction, etc.).
Referring to the exemplary embodiment shown in FIGS. 7 and 9, rungs
42 extend laterally between the base rails 46 of the truss members
40. The rungs 42 facilitate the ascent and descent of a fire
fighter or a person being aided by the fire fighter along aerial
ladder assembly 30. In an exemplary embodiment, the rungs 42 are
coupled to the inner side wall 64 of the second members 56 of the
truss members 40. In other embodiments, the rungs 42 are coupled to
the top walls or the bottom walls of the first member 54 and the
second member 56. The rungs 42 may also be coupled to braces 68
disposed along base rails 46.
In an exemplary embodiment, the rungs 42 are thin-walled, tubular
members thereby reducing the weight of the aerial ladder assembly
30. Rungs 42 may have a cross-sectional shape (e.g., round,
elliptical, D-shaped, etc.) that facilitates the engagement thereof
(e.g., grasping, stepping, etc.) by a fire fighter or a person
being aided by the fire fighter. Rung supports 44 strengthen aerial
ladder assembly 30, according to an exemplary embodiment. In one
embodiment, rung supports 44 are coupled to rungs 42. Rungs 42 and
rung supports 44 may define a plurality of braces (e.g., K-braces,
etc.) that couple the truss members 40 together. The rung supports
44 are a V-shaped members that are coupled to the rungs 42 at a
point between the two truss members 40. In an exemplary embodiment,
the rung supports 44 are positioned rearward of (e.g., toward the
first end 32 relative to, etc.) the rungs 42. The rung supports 44
include a pair of arms 110 extending between the rungs 42 and base
rails 46. In one embodiment, the arms 110 are connected by a
transition portion 112 that is coupled (e.g., welded, etc.) to the
rung 42. In other embodiments, the rung supports 44 may not include
the transition portions 112, and the arms 110 may be separate
members that are coupled directly to the rungs 42. As shown in FIG.
9, the distal ends of the arms 110 are coupled to the base rails
46.
In an exemplary embodiment, rung supports 44 are formed from a
plate with one or more bending operations. As shown in FIG. 9, the
rung supports 44 include a main body 114, a first flange 116 that
extends downward from a rearward edge of the main body 114, and a
pair of flanges 118 that extend downward form a forward edge of the
main body 114. The rung supports 44 have a reduced weight compared
to a brace formed of thin-walled tubular members or other
traditional designs while providing lateral strength and stiffness
to the aerial ladder assembly 30. In other embodiments, the rung
supports 44 are thin-walled tubular members. The size and shape of
the rung supports 44 (e.g., wall thickness, width of the main body,
height of the flanges 106 and 108, angle of the arms 110, etc.) may
vary along the length of the ladder. For example, the rung supports
44 provided along the first zone 80 of the aerial ladder assembly
30 may be configured to resist greater lateral forces than the rung
supports 44 provided along the second zone 82 of the aerial ladder
assembly 30. Aerial ladder assembly 30 has a reduced weight due to
the configuration of rung supports 44 (e.g., the weight of the rung
supports 44 and the weight of the aerial ladder assembly 30 is
reduced by not configuring all of the rung supports 44 to be
capable of supporting the maximum lateral forces, etc.).
According to the alternative embodiment shown in FIG. 10, the
aerial ladder assembly 30 includes a plurality of telescoping
ladder sections including a first ladder section, shown as first
ladder section 200, a second ladder section, shown as second ladder
section 300, and a third ladder section, shown as third ladder
section 400. As shown in FIG. 10, the aerial ladder assembly 30
includes three sections. In other embodiments, the aerial ladder
assembly 30 has more or fewer ladder sections (e.g., two sections,
four sections, five sections, etc.).
According to the exemplary embodiment shown in FIG. 10, the first
ladder section 200 includes a first base rail, shown as base rail
210, a first lacing member, shown as lacing member 220, and a first
rung member, shown as rung member 230. As shown in FIG. 10, the
base rail 210 is defined by wall 212, wall 214, wall 216, and wall
218. Each wall is coupled perpendicularly to an adjacent wall,
forming a substantially rectangular cross-sectional shape. As shown
in FIG. 10, wall 212, wall 214, wall 216, and wall 218 have a
common length such that base rail 210 has a generally square
cross-sectional shape. In other embodiments, the base rail 210 may
have another cross-sectional shape (e.g., triangular, circular,
hexagonal, etc.). A corner is defined at each of the points where
adjacent walls intersect. As shown in FIG. 10, the base rail 210
includes four corners, shown as corner 211, corner 213, corner 215,
and corner 217. According to an exemplary embodiment, corner 211
and corner 215 are horizontally-aligned while corner 213 and corner
217 are vertically-aligned. It should be understood that, while
shown in the cross-sectional view of FIG. 10 as corners, corner
211, corner 213, corner 215, and corner 217 may define edges that
extend along the length of base rail 210.
The lacing member 220 includes a first end (e.g., proximal end,
base end, etc.), shown as first end 222, and a second end (e.g.,
distal end, railing end, etc.), shown as second end 224. As shown
in FIG. 10, the lacing member 220 defines an axis, shown as axis
226, which is disposed along a centerline of the lacing member 220.
In one embodiment, axis 226 is positioned vertically. In other
embodiments, lacing member 220 is tilted (e.g., tilted outward from
a centerline of the first ladder section 200, etc.) such that axis
226 is angularly offset relative to a vertical axis. Lacing member
220 may have various cross-sectional shapes (e.g., circular,
rectangular, square, etc.). As shown in FIG. 10, the first end 222
of the lacing member 220 abuts the wall 212 and the wall 214 of the
base rail 210. In one embodiment, base rail 210 is positioned such
that corner 213 and corner 217 are positioned along axis 226. Base
rail 210 may thereby have a substantially diamond-shaped
configuration. The second end 224 of the lacing member 220 may
extend toward a hand rail. The rung member 230 includes a first
end, shown as first end 232, and a second end, shown as second end
234. The rung member 230 defines an axis, shown as axis 236, which
is disposed along a centerline of the rung member 230. In one
embodiment, axis 236 is positioned horizontally. Rung member 230
may have various cross-sectional shapes (e.g., circular, square,
rectangular, etc.). The first end 232 of the rung member 230 abuts
the wall 214 and the wall 216 of the base rail 210. In one
embodiment, base rail 210 is positioned such that corner 211 and
corner 215 are disposed along axis 236. The second end 234 of the
rung member 230 may extend toward a second base rail 210.
Referring still to FIG. 10, a channel member, shown as channel
member 260, is attached to an interior surface of the lacing member
220 (e.g., a surface disposed laterally inward and facing a
centerline of the first ladder section 200, etc.). As shown in FIG.
10, the channel member 260 includes a base 262 that abuts the
lacing member 220, a first flange 264, and a second flange 266. The
channel member 260 is configured to receive a first slide pad,
shown as slide pad 240. The slide pad 240 includes a notch, shown
as notch 242. A second slide pad, shown as slide pad 250, directly
abuts the rung member 230. The slide pad 250 also includes a notch,
shown as notch 252. In other embodiments, at least one of slide pad
240 and slide pad 250 has another cross-sectional shape. According
to an alternative embodiment, at least one of slide pad 240 and
slide pad 250 are otherwise coupled to lacing member 220 and rung
member 230 or coupled to still another component of first ladder
section 200.
According to the exemplary embodiment shown in FIG. 10, the second
ladder section 300 includes a first base rail, shown as base rail
310, a first lacing member, shown as lacing member 320, and a first
rung member, shown as rung member 330. As shown in FIG. 10, the
base rail 310 is defined by wall 312, wall 314, wall 316, and wall
318. Each wall is coupled perpendicularly to an adjacent wall,
forming a substantially rectangular cross-sectional shape. As shown
in FIG. 10, wall 312, wall 314, wall 316, and wall 318 have a
common length such that base rail 310 has a generally square
cross-sectional shape. In other embodiments, the base rail 310 may
have another cross-sectional shape (e.g., triangular, circular,
hexagonal, etc.). A corner is defined at each of the points where
adjacent walls intersect. As shown in FIG. 10, the base rail 310
includes four corners, shown as corner 311, corner 313, corner 315,
and corner 317. According to an exemplary embodiment, corner 311
and corner 315 are horizontally-aligned while corner 313 and corner
317 are vertically-aligned. It should be understood that, while
shown in the cross-sectional view of FIG. 10 as corners, corner
311, corner 313, corner 315, and corner 317 may define edges that
extend along the length of base rail 310.
The lacing member 320 includes a first end (e.g., proximal end,
base end, etc.), shown as first end 322, and a second end (e.g.,
distal end, railing end, etc.), shown as second end 324. As shown
in FIG. 10, the lacing member 320 defines an axis, shown as axis
326, which is disposed along a centerline of the lacing member 320.
In one embodiment, axis 326 is positioned vertically. In other
embodiments, lacing member 320 is tilted (e.g., tilted outward from
a centerline of the second ladder section 300, etc.) such that axis
326 is angularly offset relative to a vertical axis. Lacing member
320 may have various cross-sectional shapes (e.g., circular,
rectangular, square, etc.). As shown in FIG. 10, the first end 322
of the lacing member 320 abuts the wall 312 and the wall 314 of the
base rail 310. In one embodiment, base rail 310 is positioned such
that corner 313 and corner 317 are positioned along axis 326. Base
rail 310 may thereby have a substantially diamond-shaped
configuration. The second end 324 of the lacing member 320 may
extend toward a hand rail. The rung member 330 includes a first
end, shown as first end 332, and a second end, shown as second end
334. The rung member 330 defines an axis, shown as axis 336, which
is disposed along a centerline of the rung member 330. In one
embodiment, axis 336 is positioned horizontally. Rung member 330
may have various cross-sectional shapes (e.g., circular, square,
rectangular, etc.). The first end 332 of the rung member 330 abuts
the wall 314 and the wall 316 of the base rail 310. In one
embodiment, base rail 310 is positioned such that corner 311 and
corner 315 are disposed along axis 336. The second end 334 of the
rung member 330 may extend toward a second base rail 310.
Referring still to FIG. 10, a channel member, shown as channel
member 360, is attached to an interior surface of the lacing member
320 (e.g., a surface disposed laterally inward and facing a
centerline of the second ladder section 300, etc.). As shown in
FIG. 10, the channel member 360 includes a base 362 that abuts the
lacing member 320, a first flange 364, and a second flange 366. The
channel member 360 is configured to receive a first slide pad,
shown as slide pad 340. The slide pad 340 includes a notch, shown
as notch 342. A second slide pad, shown as slide pad 350, directly
abuts the rung member 330. The slide pad 350 also includes a notch,
shown as notch 352. In other embodiments, at least one of slide pad
340 and slide pad 350 has another cross-sectional shape. According
to an alternative embodiment, at least one of slide pad 340 and
slide pad 350 are otherwise coupled to lacing member 320 and rung
member 330 or coupled to still another component of second ladder
section 300.
According to the exemplary embodiment shown in FIG. 10, the third
ladder section 400 includes a first base rail, shown as base rail
410, a first lacing member, shown as lacing member 420, and a first
rung member, shown as rung member 430. As shown in FIG. 10, the
base rail 410 is defined by wall 412, wall 414, wall 416, and wall
418. Each wall is coupled perpendicularly to an adjacent wall,
forming a substantially rectangular cross-sectional shape. As shown
in FIG. 10, wall 412, wall 414, wall 416, and wall 418 have a
common length such that base rail 410 has a generally square
cross-sectional shape. In other embodiments, the base rail 410 may
have another cross-sectional shape (e.g., triangular, circular,
hexagonal, etc.). A corner is defined at each of the points where
adjacent walls intersect. As shown in FIG. 10, the base rail 410
includes four corners, shown as corner 411, corner 413, corner 415,
and corner 417. According to an exemplary embodiment, corner 411
and corner 415 are horizontally-aligned while corner 413 and corner
417 are vertically-aligned. It should be understood that, while
shown in the cross-sectional view of FIG. 10 as corners, corner
411, corner 413, corner 415, and corner 417 may define edges that
extend along the length of base rail 410.
The lacing member 420 includes a first end (e.g., proximal end,
base end, etc.), shown as first end 422, and a second end (e.g.,
distal end, railing end, etc.), shown as second end 424. As shown
in FIG. 10, the lacing member 420 defines an axis, shown as axis
426, which is disposed along a centerline of the lacing member 420.
In one embodiment, axis 426 is positioned vertically. In other
embodiments, lacing member 420 is tilted (e.g., tilted outward from
a centerline of the third ladder section 400, etc.) such that axis
426 is angularly offset relative to a vertical axis. Lacing member
420 may have various cross-sectional shapes (e.g., circular,
rectangular, square, etc.). As shown in FIG. 10, the first end 422
of the lacing member 420 abuts the wall 412 and the wall 414 of the
base rail 410. In one embodiment, base rail 410 is positioned such
that corner 413 and corner 417 are disposed along axis 426. Base
rail 410 may thereby have a substantially diamond-shaped
configuration. The second end 424 of the lacing member 420 may
extend toward a hand rail. The rung member 430 includes a first
end, shown as first end 432, and a second end, shown as second end
434. The rung member 430 defines an axis, shown as axis 436, which
is disposed along a centerline of the rung member 430. In one
embodiment, axis 436 is positioned horizontally. Rung member 430
may have various cross-sectional shapes (e.g., circular, square,
rectangular, etc.). The first end 432 of the rung member 430 abuts
the wall 414 and the wall 416 of the base rail 410. In one
embodiment, base rail 410 is positioned such that corner 411 and
corner 415 are disposed along axis 436. The second end 434 of the
rung member 430 may extend toward a second base rail 410.
According to the exemplary embodiment shown in FIG. 10, first
ladder section 200 is configured to receive second ladder section
300. As shown in FIG. 10, notch 242 of slide pad 240 and notch 252
of slide pad 250 have a cross-sectional shape that corresponds to a
cross-sectional shape of base rail 310 of second ladder section
300. Notch 242 and notch 252 may thereby receive corner 311 and
corner 317 of base rail 310, respectively. An actuator may be used
to extend and retract second ladder section 300 from first ladder
section 200. During actuation (e.g., extension, retraction, etc.),
base rail 310 of second ladder section 300 may slide along slide
pad 240 and slide pad 250, within notch 242 and notch 252. Second
ladder section 300 is configured to receive third ladder section
400. As shown in FIG. 10, notch 342 of slide pad 340 and notch 352
of slide pad 350 have a cross-sectional shape that corresponds to a
cross-sectional shape of base rail 410 of third ladder section 400.
Notch 342 and notch 352 may thereby receive corner 411 and corner
417 of base rail 410, respectively. An actuator may be used to
extend and retract third ladder section 400 from second ladder
section 300. During actuation (e.g., extension, retraction, etc.),
base rail 410 of third ladder section 400 may slide along slide pad
340 and slide pad 350, within notch 342 and notch 352. In other
embodiments, third ladder section 400 includes slide pads shaped to
receive an additional ladder section (e.g., a fly section, etc.).
Such slide pads may be shaped and interact in a manner like those
of first ladder section 200 and second ladder section 300.
According to an exemplary embodiment, the ladder assembly includes
base rails that are positioned such that loading imparted by the
lacing members and that rungs is directed into corners of the base
rails. The ladder assembly may also include slide pads shaped to
receive the base rails (e.g., corners of the base rails, etc.) such
that stresses transferred between ladder sections also flow through
the corners of the base rails. In one embodiment, positioning and
configuring the base rails, slide pads, lacing members, and rungs
to direct loading through the corners of the base rails reduces
weight, improves strength, and enhances the horizontal reach of the
ladder assembly.
It is important to note that the construction and arrangement of
the elements of the systems and methods as shown in the exemplary
embodiments are illustrative only. Although only a few embodiments
of the present disclosure have been described in detail, those
skilled in the art who review this disclosure will readily
appreciate that many modifications are possible (e.g., variations
in sizes, dimensions, structures, shapes and proportions of the
various elements, values of parameters, mounting arrangements, use
of materials, colors, orientations, etc.) without materially
departing from the novel teachings and advantages of the subject
matter recited. For example, elements shown as integrally formed
may be constructed of multiple parts or elements. It should be
noted that the elements and/or assemblies of the components
described herein may be constructed from any of a wide variety of
materials that provide sufficient strength or durability, in any of
a wide variety of colors, textures, and combinations. Accordingly,
all such modifications are intended to be included within the scope
of the present inventions. Other substitutions, modifications,
changes, and omissions may be made in the design, operating
conditions, and arrangement of the preferred and other exemplary
embodiments without departing from scope of the present disclosure
or from the spirit of the appended claims.
* * * * *
References